JP2008267275A - Vane pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vane pump improved in pump efficiency at a time of start, and the suction and discharge of a high viscosity fluid, and capable of reducing manufacturing cost by a simple structure. <P>SOLUTION: The vane pump is provided with a rotor 8 arranged in such a manner that the rotor can rotate around a turning canter C1, and a vane 9 attached on a rotor outer circumference with an attachment part 9c in such a manner that the rotor can rotate around a turning center C2 in parallel with the turning center C1 and separate from the turning center C1 in a circumference direction. The vane 9 includes a first part 9a positioned at one side in the circumference direction with respect to the turning center C2 and a second part 9b positioned at the other side. Outer circumference surface cams 4A, 4B comprising outer races of circular radial bearings capable of abutting on projections 9a1, 9a2 of the vane first part 9a are retained on casing side plates 2A, 2B eccentrically from the turning center C1. Outer diameters of the outer circumference surface cams 4A, 4B are smaller than double of a distance from the turning center C1 to the turning center C2. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vane pump, and more particularly to a vane pump that feeds an incompressible fluid at a relatively low pressure.

  Conventionally, as a vane pump, a rotor is attached to a rotating shaft that extends between two side plates so as to be orthogonal to the two side plates, and a plurality of radiations arranged along the rotor rotating direction (circumferential direction) on the outer peripheral surface of the rotor. In which a vane is accommodated in each groove, and a cam ring having an inner peripheral surface that is in contact with or close to the outer edge of the vane on the outer side in the radial direction with respect to the rotor. It is used. As the rotor rotates, the fluid sucked through the suction port is fed and discharged through the discharge port.

  In such a vane pump, the vane is urged against the inner circumferential cam surface by the centrifugal force accompanying the rotation of the rotor. However, in a state where the rotor rotation is stopped, the force for urging the vane against the inner circumferential cam surface does not act, so the outer edge of the vane moves away from the inner circumferential cam surface. For this reason, immediately after starting the rotor rotation, that is, at the time of starting the pump, there is a problem in that the vane is not sufficiently popped out of the groove and it takes time until a satisfactory pumping action can be performed. This is a problem that occurs not only when the rotor rotation is completely stopped, but also when the rotor rotational speed is low. Further, when the viscosity of the fluid to be sucked and discharged is high, even when the rotor rotational speed is high, the vane is ejected from the groove by the centrifugal force accompanying the rotor rotation and moved toward the inner circumferential cam surface. Since the speed decreases, the contact or proximity between the vane and the inner peripheral cam surface cannot be sufficiently maintained, and fluid leakage may occur, resulting in a decrease in pump efficiency.

  In order to solve such problems, a vane pump proposed in Japanese Patent Application Laid-Open No. H8-219032 (Patent Document 1) employs the following configuration.

That is, a drive rotary shaft is inserted into the casing, and a rotor having a hollow cylindrical portion in the direction of the drive rotary shaft is attached to the drive rotary shaft in the casing, and the hollow cylindrical portion of the rotor Are formed with a plurality of radial and axial slits arranged along the circumferential direction of the drive rotation shaft, and vanes are slidably inserted in each of the slits in the radial direction. Yes. Here, a first cam member having an outer circumferential cam surface is disposed radially inward of the rotor hollow cylindrical portion, and an inner circumferential cam surface is disposed radially outward of the rotor hollow cylindrical portion. A second cam member is disposed. Each of the vanes has an inner edge that can contact the outer peripheral cam surface of the first cam member, and an outer edge that can contact the inner peripheral cam surface of the second cam member. The outer peripheral surface of the rotor and the inner peripheral surface of the second cam member are in contact at a specific position in the circumferential direction of the rotating shaft. A fluid flow path is formed through a circumferential position opposite to the specific circumferential position, and the fluid flow path includes an outer peripheral surface of the rotor, an inner peripheral surface of the second cam member, and a side surface of the casing. And is formed by. The outer peripheral cam surface of the first cam member and the inner peripheral cam surface of the second cam member have corresponding shapes.
JP-A-8-219032

  However, in the vane pump described in Patent Document 1 as described above, it is necessary to form two cam surfaces, that is, an inner peripheral cam surface and an outer peripheral cam surface, so that the cam surface is expensive to manufacture. Furthermore, since cam members are required both radially inward and radially outward of the rotor hollow cylindrical portion, there is a problem that the structure is complicated.

  In view of the technical problems as described above, the present invention provides a vane pump that has good pump efficiency at start-up and good pump efficiency at the time of suction and discharge of high-viscosity fluid, has a simple structure, and can reduce manufacturing costs. It is intended to provide.

According to the present invention, the object as described above is achieved.
A casing,
A rotor arranged to be rotatable around a center of rotation within the casing;
A plurality of vanes attached to the outer periphery of the rotor so as to be rotatable around a plurality of rotation centers that are parallel to the rotation center and separated from each other in the circumferential direction;
Each of the vanes has a first portion located on one side with respect to the rotation center with respect to the rotation center, and a second portion positioned on the other side with respect to the rotation direction with respect to the rotation center. And
The casing holds a circular outer peripheral surface cam that is eccentric from the rotation center and capable of contacting the first portion of the vane,
A vane pump, wherein an outer diameter of the outer peripheral surface cam is smaller than twice a distance from the rotation center to the rotation center;
Is provided.

  In one aspect of the present invention, the outer circumferential cam is rotatable with respect to the casing about its center. In one aspect of the present invention, the outer peripheral cam is composed of a radial bearing outer race.

  In one aspect of the present invention, the first portion of the vane has a protruding portion that protrudes in the direction of the rotation center, and the protruding portion contacts the outer peripheral cam. In one aspect of the present invention, the outer peripheral surface cam is accommodated in a cam groove provided in a side plate portion constituting the casing.

  In an aspect of the present invention, the outer peripheral surface cam is positioned on the inner side of a rotation trajectory of the rotation center around the rotation center. In one aspect of the present invention, a concave portion is formed in the outer peripheral portion of the rotor to accommodate the first portion of the vane as the rotor rotates.

  In one aspect of the present invention, the second portion of the vane is concave in the direction of rotation of the rotor. In one aspect of the present invention, the plurality of vanes are equally arranged with respect to the rotor rotation direction.

  According to the vane pump of the present invention, a plurality of vanes are attached to the outer peripheral portion of the rotor so as to be rotatable, the circular outer peripheral surface cam that is eccentric from the rotor rotation center and can contact the first portion of the vane is provided. A new structure is adopted in which the outer diameter cam is held by a casing and the outer diameter of the outer peripheral surface cam is made smaller than twice the distance from the rotor rotation center to the vane rotation center. The pump efficiency at the time of sucking and discharging the viscous fluid is good, the structure is simple, and the manufacturing cost can be reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is an exploded perspective view showing an embodiment of a vane pump according to the present invention, and FIGS. 2 and 3 are sectional views of the vane pump of this embodiment.

  In the vane pump of the present embodiment, a substantially cylindrical rotor 8 is disposed in the casing 2. The casing 2 is formed by disposing a casing body 2C between a pair of casing side plates 2A and 2B, and connecting and integrating them by screwing. A drive rotary shaft 6 is inserted into the casing 2. The drive rotary shaft 6 is supported by the casing side plate portions 2A and 2B so as to be rotatable around the rotation center C1 via bearings 1A and 1B, respectively. Within the casing 2, a rotor 8 is key-coupled to the drive rotary shaft 6. The drive rotary shaft 6 is connected to a rotary drive means (not shown) such as an electric motor outside the casing 2.

  In the following description, the direction of the drive rotary shaft 6, that is, the direction of the rotation center C <b> 1 or the direction parallel thereto is referred to as the axial direction, the circular direction centered on this axial direction is referred to as the circumferential direction, and the axial direction is the center. A direction orthogonal to the direction is referred to as a radial direction.

  Both ends of the four rotation shafts 7 are supported on the outer peripheral portion of the rotor 8 so as to be rotatable around a rotation center C2 parallel to the rotation center C1. These four rotation shafts 7 are equally arranged with respect to the rotation direction of the rotor (that is, every 90 degrees around the rotation center C1). A vane 9 is attached to the rotating shaft 7. The vane 9 has a first portion 9a located on one side with respect to the circumferential direction with respect to the rotation center C2 and a second portion 9b located on the other side with respect to the circumferential direction with respect to the rotation center C2. . A portion for attaching the vane 9 to the rotating shaft 7 is denoted by reference numeral 9c.

  As shown in FIG. 2, the four vanes 9 are arranged in the same direction with respect to the circumferential direction around the rotation center C1. In FIG. 2, the rotor rotation direction is indicated by an arrow R <b> 1, and each vane 9 has a first portion 9 a positioned rearward with respect to the rotor rotation direction R <b> 1 and a second portion 9 b positioned forward with respect to the rotor rotation direction. Further, the vane 9, particularly the second portion 9b thereof, is curved and has a concave shape toward the rotation center C1 or toward the rotor rotation direction R1. Protrusions 9a1 and 9a2 projecting to both sides in the direction of the rotation center C1 are formed at the tip of the first portion 9a of the vane 9.

  The casing side plate portion 2A is formed with a cam groove 2A1 having a circular shape with a center C3 (parallel to the rotation center C1) eccentric from the rotation center C1 on the inner surface of the casing. A radial bearing 4A is disposed in the cam groove 2A1. The radial bearing 4A has an inner race 4A1 fixed to the inner wall surface of the circular cam groove 2A1, and the outer race 4A2 is around the center C3 with respect to the inner race 4A1 (and with respect to the casing 2). It can be rotated. The outer race 4A2 of the radial bearing 4A functions as the outer peripheral surface cam of the present invention. That is, the protruding portion 9a1 of each vane is accommodated in the cam groove 2A1, and can contact the outer surface of the outer race 4A2.

  The casing side plate portion 2B also has the same structure as the casing side plate portion 2A. That is, a cam groove 2B1 having a circular shape with a center C3 that is eccentric from the rotation center C1 by the same amount as the cam groove 2A1 is formed on the inner surface of the casing side plate portion 2B. That is, the cam groove 2A1 and the cam groove 2B1 are coaxial. A radial bearing 4B similar to the radial bearing 4A is disposed in the cam groove 2B1. The radial bearing 4B has its inner race 4B1 fixed to the inner wall surface of the circular cam groove 2B1, and the outer race 4B2 is around the center C3 with respect to the inner race 4B1 (and with respect to the casing 2). It can be rotated. The outer race 4B2 of the radial bearing 4B functions as the outer peripheral surface cam of the present invention. That is, the protruding portion 9a2 of each vane is accommodated in the cam groove 2B1, and can contact the outer surface of the outer race 4B2.

  As can be seen from FIGS. 2 and 3, the outer diameters (diameters) of the outer races 4A2 and 4B2 functioning as the outer peripheral cams are smaller than twice the distance from the rotation center C1 to the rotation center C2. Further, the eccentric amount D of the center C3 with respect to the rotation center C1 is such that the outer races 4A2 and 4B2 are positioned inside the rotation locus (cylindrical surface shape) of the rotation center C2 around the rotation center C1. Is set.

  In the outer peripheral portion of the rotor 8, a recess 81 is formed in which the first portion 9 a of each vane 9 is accommodated as the rotor rotates.

  A space V in which the rotor 8 and the vane 9 can rotate around the rotation center C1 is formed in the casing body 2C. That is, when the drive rotation shaft 6 is rotated around the rotation center C1 (counterclockwise in FIG. 2) in the direction of the arrow R1 by a rotation driving means (not shown) such as an electric motor, the rotor 8 is also integrated with the arrow R1. Rotate in the direction of. The protrusions 9a1 and 9a2 of each vane 9 are subjected to contact with the cam races 2A1 and 2B1, particularly the outer races 4A2 and 4B2 of the bearings 4A and 4B accommodated therein, and the fluid is applied to each vane 9, particularly the second portion 9b. The vanes 9 rotate around the rotation center C2 based on the resistance force acting on the. Thereby, the tip of the second portion 9b of each vane 9 moves through the path T shown in FIG. The shape of the space V is formed so as to include the path T as described above, and is formed slightly larger than the path T.

  The casing body 2C is formed with a suction port 12 for sucking fluid and a discharge port 14 for discharging the sucked fluid. The suction port 12 and the discharge port 14 communicate with the space V at positions opposite to each other. Thus, when the vane 9 moves along the path T as the rotor 8 rotates, the vane 9 rotates while the protrusions 9a1 and 9a2 of the vane first portion are located above the rotation center C1 in FIG. The vane 9 rotates counterclockwise around the rotation center C2 while rotating clockwise around the center C2 and while the protrusions 9a1 and 9a2 of the vane first portion are located below the rotation center C1 in FIG. Rotate. During this time, the concave surface of the vane second portion 9b receives the resistance of the liquid in the space V, and the protrusions 9a1 and 9a2 of the vane first portion receive a repulsive force from the outer races 4A2 and 4B2 of the bearing. Here, since the outer races 4A2 and 4B2 can rotate around the center C3 with respect to the casing 2, the outer races 4A2 and 4B2 rotate around the center C3 together with the first portion 9a of the vane 9. Thus, the rotation of the rotor 8 is performed smoothly.

  Further, in FIG. 2, the tip of the second portion 9b of the vane 9 from the outer peripheral surface of the vane is longer when the protrusions 9a1 and 9a2 of the vane first portion are positioned to the left than the rotation center C1 as compared with the case where the protrusions The height H is large. In accordance with the height H, the amount of the vane first portion 9a entering the recess 81 changes. Thus, in FIG. 2, a sufficiently large cross-sectional fluid flow path from the suction port 12 to the discharge port 14 is formed below the rotor 8, and the fluid is sucked from the suction port 12 in the direction of the arrow R2 and discharged. It can be discharged from the outlet 14 in the direction of the arrow R3.

  In the above embodiment, since the vane 9 is in the form of a so-called Yajirobei, the tip of the first portion 9a can be disposed closer to the rotation center C1 than the rotation center C2, and thus the cam groove The diameter can be reduced. For this reason, it is easy to use the outer races 4A2 and 4B2 of the bearing as the outer peripheral surface cam, and based on this, it is easy to smooth the rotation of the rotor 8.

  Further, in the present embodiment, as is clear from the above description, even when the pump is started up or even if the fluid has a high viscosity, the vane 9 rises (rises) and falls ( Since the (falling) operation is performed reliably and regularly, a sufficiently good pump efficiency can be obtained.

  In the above embodiment, the number of vanes 9 attached to the rotor is 4, but the present invention is not limited to this, and the number of vanes may be 2, 3 or 5 or more. Further, in the above embodiment, the first portion 9a of the vane has the protruding portions 9a1 and 9a2 formed on both sides, that is, both ends in the axial direction, but the present invention is not limited to this. The protruding portion may be provided only at one end in the axial direction.

It is a disassembled perspective view which shows one Embodiment of the vane pump by this invention. It is sectional drawing of the vane pump of FIG. It is sectional drawing of the vane pump of FIG.

Explanation of symbols

2 Casing 2A, 2B Casing side plate 2A1, 2B1 Cam groove 2C Casing body 4A, 4B Radial bearings 4A1, 4B1 Inner race 4A2, 4B2 Outer race 6 Drive rotating shaft 7 Rotating shaft 8 Rotor 81 Recess 9 Vane 9a First part 9a1, 9a2 Protruding portion 9b Second portion 9c Attachment portion 12 Suction port 14 Discharge port C1 Rotation center C2 Rotation center C3 Center V Space

Claims (9)

A casing,
A rotor arranged to be rotatable around a center of rotation within the casing;
A plurality of vanes attached to the outer periphery of the rotor so as to be rotatable around a plurality of rotation centers that are parallel to the rotation center and separated from each other in the circumferential direction;
Each of the vanes has a first portion located on one side with respect to the rotation center with respect to the rotation center, and a second portion positioned on the other side with respect to the rotation direction with respect to the rotation center. And
The casing holds a circular outer peripheral surface cam that is eccentric from the center of rotation and capable of contacting the first portion of the vane,
The vane pump according to claim 1, wherein an outer diameter of the outer peripheral cam is smaller than twice a distance from the rotation center to the rotation center. The vane pump according to claim 1, wherein the outer circumferential cam is rotatable with respect to the casing around a center thereof. The vane pump according to claim 2, wherein the outer peripheral surface cam is formed of an outer race of a radial bearing. The first portion of the vane has a protruding portion that protrudes in the direction of the rotation center, and the protruding portion abuts on the outer peripheral surface cam. Vane pump as described in. 5. The vane pump according to claim 4, wherein the outer peripheral surface cam is accommodated in a cam groove provided in a side plate portion constituting the casing. The vane pump according to any one of claims 1 to 5, wherein the outer peripheral surface cam is positioned inside a rotation trajectory of the rotation center around the rotation center. The vane pump according to any one of claims 1 to 6, wherein a concave portion in which the first portion of the vane is accommodated as the rotor rotates is formed on an outer peripheral portion of the rotor. . The vane pump according to any one of claims 1 to 7, wherein the second portion of the vane has a concave shape in the direction of rotation of the rotor. The vane pump according to any one of claims 1 to 8, wherein the plurality of vanes are arranged equally with respect to the rotor rotation direction.

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